Ok, I think I figured it out. You have to have async keyword on all the methods going up above this one, and call await on the show. In my case, that required adding async keyword to the anonymous function that I had for the event handler of the menu that I pressed the button for. (It then calls await MessageBox.Show () and that puts up the messagebox. A lot of screwing around for iOS 7, but then, that is what iOS 7 is – a lot of screwing around for nothing. (Sigh)